The embodiments herein relate to propping fractures in subterranean formations and, more particularly, to propping fractures in subterranean formations using memory particulates.
Subterranean wells (e.g., hydrocarbon producing wells, water producing wells, and the like) are often stimulated by hydraulic fracturing treatments. In hydraulic fracturing treatments, a viscous treatment fluid is pumped into a portion of a subterranean formation at a rate and pressure such that the subterranean formation breaks down and one or more fractures are formed therein. Particulate solids, such as graded sand, are typically suspended in at least a portion of the treatment fluid and deposited into the fractures in the subterranean formation. These particulate solids, or “proppants particulates” (also referred to simply as “proppants”) serve to prop the fracture open (e.g., keep the fracture from fully closing) after the hydraulic pressure is removed. By keeping the fracture from fully closing, the proppant particulates aid in forming conductive paths through which produced fluids, such as hydrocarbons, may flow.
The degree of success of a fracturing operation depends, at least in part, upon fracture porosity and conductivity once the fracturing operation is complete and production is begun. Traditional fracturing operations place a volume of proppant into a fracture to form a “proppant pack” in order to ensure that the fracture does not close completely upon removing the hydraulic pressure. The ability of the proppants to maintain a fracture open depends upon the ability of the proppant to withstand fracture closure pressures. The porosity of a proppant pack within a fracture is related to the interconnected interstitial spaces between abutting proppants. Thus, the fracture productivity is closely related to the strength of the placed proppant particulates and the interstitial spaces between the proppant particulates in the proppant pack.
In some fracturing operations, a large volume of proppant particulates may be placed within the fracture to form a tight proppant pack. In other fracturing operations, a much reduced volume of proppant particulates may be placed in the fracture to create larger interstitial spaces between the proppant particulates. However, both fracturing approaches may result in at least some settling of the proppants within a fracture opening. Proppant settling may lead to a fracture or a top portion of a fracture closing, which may lower the conductivity of the proppant fracture and result in proppant masses having little or no interstitial spaces at the bottom portion of a fracture, thereby further decreasing the conductivity of the fracture. Proppant settling may be particularly problematic in cases where proppant aggregates are used in place of traditional proppant particulates because the proppant aggregates tend to be larger and may be heavier and, thus, more difficult to hold in suspension. While settling may be counteracted by using a high pump rate or by increasing the viscosity of the fluid carrying the proppant particulates or proppant aggregates, such methods often lose effectiveness once the fluid comprising the proppant or aggregates is placed into a fracture and before the hydraulic pressure is released.